Sear control mechanism for automatic firearms



Aug. 14, 1945. H. LIPPERT 2,381,916

SEAR CONTROL MECHANISM FOR AUTOMATIC FIREARMS Filed June 14, 1940 5 Sheets-Sheet l fiver day: HAN/vs L 1 52 7 H. LIPPERT Aug. 14, 1945.

SEAR CONTROL MECHANISM FOR AUTOMATIC FIREARMS Filed June 14, 1940 5 Sheets-Sheet 2 \NVENTOR H L /PPER7' BY 9L ATTORNEYS 1945- H. LIPPERT 2,331,915

SEAR CONTROL MECHANISM FOR AUTOMATIC FIREARMS Filed June 14, 1940 3 Sheets-Sheet 3 INVENTOR /7. L/PPERT ATTOR NEYS Patented Aug. 14, 1945 2,381,916 SEAR CONTROL MECHANISM FOR AUTOMA TIC FIREARMS R Hanna Llppert, Zurich, Switzerland Application June 14, 1940, Serial No. 340,499

In Switzerland June 17, 1939 I 7 Claims. (CI. 89-27) My invention relates to a modification of or improvements in the trigger and sear control mechanisms for automatic firearms firing on advance movements of the breech block, and controlled either locally or remotely.

My invention relates particularly to the remote control of the trigger and sear mechanism by means of Bowden cables, in which by the arrangement of a device which becomes operative after the release of the remote control, a locking member is positively carried back into the locking position. j

My invention consists in complementing the locking means, whereby it is possible to make the weapons for remote or direct control. The improved device has four levers hingedly connected together and arranged in the manner of a foursided linkage system, of which one at the same time forms the locking member released on uncocking, another one is in operative connection with the service members, and a third cooperates" with the breech closure body.

The spring buffer can be fitted in the closure body, so that all the parts of the sear control can be carried unsprung directly in the sear control housing. the mass locked closure system itself the, spring buifer in the closure body must not excessively load the moving masses, it is in the scope of a further improvement of the weapon to shift the spring buffer into the sear control arrangement.

The accompanying drawings show a construction for carrying out the invention, by way of example.

In said drawings,

Figure l is a sectional elevation of a portion of a machine gun including the sear mechanism;

Figure 2 is a similar view with the sear device in the cooked position;

Figures 3 and 4 are vertical sections showing a portion of the part of the sear device not located in the sectional plane of Figures 1 and 2;

Figure 5 is a plan view of the structure shown in Fig. 3, the cover being removed.

In Figure 1, l indicates the breech closure housing of a machine gun, which merges into a control mechanism casing 2. The covers 13 and 4 enclose the latter at the top and to the rear. The breech closure body or block 5 projects into the control mechanism-casing 2 by an extension 5a carrying a sprung pawl 6. The sear hook 9 is carried in a slidable buiier casing l. The buffer springs 8 are arranged in a row around the circumference of the casing l, and are supported on the front of the control mechanism casing 2 and press the Since, however, for reasons due to I casing 1 backward. where it abuts against the cover 4.

The sear hook 9 is adapted to lock the pawl 8, by

means of a downwardly directed nose piece 9a,

the pawl 6 and the sear hook Scooperating with automatically releasing surfaces. A nose piece 9b on the upper side of the sear hook 9 permits the latter to be pressed downwards in the position of rest by means of a locking lever to, see Figure 1. Two clutch forks or links H,- arranged symmetrically to the vertical central longitudinal plane of the weapon, and with stops Ila, are each hinged at one end to the locking lever l0 and at the other end to the guide links I2 which on their part are connected hingedly to the limb, located symmetrically to the vertical central longitudinal plane of the weapon, of a release lever l3 surrounding the locking lever It in loop form. The locking lever Ill, the clutch iorksor links H, the guide links l2, and the release lever l3 form with each other a kind of four-sided closed linkage system as the axes of'their connecting bolts intersect the sectional plane of Figures 1 and 2 at the four corner points of a quadrilateral. Two sprung control pawls 5b rotatably carried on the extensionv 5a of the breech closure body 5 bear against the two stops Ila. A bolt it carried in the casing l is pressed by a spring 55 against an upper arm of the locking lever it, which is rotatably carried on a pivot lta, together with the release lever it. The pivot lta is supported, at both sides in the casing l.

The pivot Ilia and a spindle 96b firmly inserted in the wall of the control mechanism casing 2 lies coaxially in the position of rest, see Figure 3. A driver l'l carried on the inner ends of the spindle I6?) is in operative connection with the release lever l3 and this by means of lateral nose pieces Ila which engages under a projection i311 of'the release lever I3. The driver t? has a nose piece lib against which the nose piece lBa of release pawl l8 provided with an arm I811 is adapted to rest.

The release pawl i8 is rotatably mounted on a pin 2|, which is fixed in a pawl carrier 20 and accompanies the rotations thereof about the spindle lBb. By means of a spring IS the nose piece l8a of the release pawl I8 is pressed against the cooperating nose piece I'lb. A further pin 20a (Figures 3, 4) fixed on the pawl carrier 20 is in constant engagement with an intermediate lever 22 in the notch 22aof which it is adapted to move. The intermediate lever 22 is fitted together with a trigger lever 23 on a spindle 24 carried in th.. casing 2, Both levers 22, 23 are held in .the normal position by a spring 22 which presses by means a spring bush 21, against a rib 22b of the intermediate lever 22. A safety nose piece 25 on a spin.. dle 22 carried in the casing 2 is adapted to be rotated so that it looks a finger 220 of the intermediate lever 22 and so secures the sear mechanism.

A release fork 3|, oscillatably carried on shaft 32 in the front part of the casing 2, is adapted to release the pawl it through its arm lib from the front side, by means of a pin 22. The release fork 3| here transmits the movement of a release rod 33, released after the last shot by the magazine supply member, on to the release pawl ll. 34 (Fig. 5) are the springs of two resetting pins 33 acting on' the release lever I-3 and which are dispowd in series with and symmetrically to 'the spring bolt ll arranged in the vertical longitudinal central plane of the weapon, in front of the quadrilateral structure II, II, l2, l3 in the casing I.

The device operates as follows:

In the position of rest, the sear mechanism takes up the position according to Figures 1 and 3. In order to place the safety device of the weapon out of operation the marksman rotates the safety nose piece 25 and thereby releases the trigger lever 23. If now the marksman pulls lever 23, the spindle 24 rotates in the direction of the arrow (Fig. 3) and with it the intermediate lever 22. The notch 22a on the latter transmits this rotation through the pin 20a on to the pawl carrier 20 which carries with it the pin 2|, the spring I! and the pawl l3. The nose piece l8a of the latter, in consequence of the action of the spring l9, remains pressed against the nose piece "b and transmits the rotation of the pawl carrier 20 to the driver ll.

Between the driver I! carried in the stationary casing 2 and the release lever l3 carried in the axially movable easing 1, there is a working connection at the point of contact of the release lever projection l3a with the driver nose piece "a, which lifts the release lever l3 and oscillates it against the pressure of the two resetting springs 34. The release lever raises the links or forks ll, until their stops Ila slide off the control pawls 5b of the extension 5a of the closing device body 5. At this instant, the spring bolt ll oscillates the locking lever l counterclockwise, as viewed in Figs. 1 and 2 about the spindle l6a. The nose piece 9b of the sear hook 9 is thereby unlocked and this moves upward and releases the closure body 5. The separate parts and in particular the foursided linkage III, II, I2, I 3 now take up the position shown in Figure 2.

Under the pressure of the forward drawing spring, not shown, the closure body springs forward and fires a cartridge. As the weapon continues to fire automatically, the firing can only be interrupted by releasing the lever 23 or by releasing the trigger mechanism after the last cartridge has left the magazine. In the first case, that is, after the firing of one or more cartridges, th' turning back of the lever 23 effects the backward rotation of the parts 22, 20, II and I1. Under the pressure of the resetting pins 35, the release lever l3 now rotates back to its normal position and lowers the links H with their stop Ila until these come into the path of the control pawls 5b. On the next forward movement of the breech body 5 from the rear reversal. the control pawls 5b drag the catch forks H forward and thereby oscillate the locking lever II which presses the sear hook -9 downward. This then the pawl l. The blow produced thereby is taken up and dampened by the recoil springs 3. The jerkymovement of the body 1 with the sear mechanism carried therein does not in any way affect its efficiency.

In the same way, the interruption of the return of the breach body I to firing position takes place when the magazine is emptied. when the last.

cartridge has left the magazine, the delivering device in the magazine presses the release rod 33 backward, as shown by Figure 4. The release fork 3| rotates with the shaft 32 and transmit the movement of the release rod 33 to the pin 29 which forces the arm llb of the release pawl l8 backward. The latter is thereby rotated about the pin 2|, whereby the nose piece Ila is brought out of engagement with the nose piece "b of the driver II. Now, even with the trigger lever 23 pulled the driver IT can be rotated back into the position of rest. Under the load of the springpressed pins 35, the parts l3, l2, II and III initiate the locking of the breech closure body 5, which is completed in the above-described manner. 0n the subsequent release of the lever 23 the nose piece 18a of the release pawl ll again comes in front of the nose piece I lb after the release rod 33 has also moved back into its nor- 'mal position. As the release parts 33, 3|, 29, I3 and I! are located in the stationary sear mechanism housing 2, they do notv accompany the movement of the buifer body I in seizing the breech closing body 5.

I claim:

1. In an automatic firearm, firing on the breech block advance movement, the combination of a housing, a breech block slidable in the housing, a releasable sear hook arranged to hold the breech block against forward movement, a sear mechanism pivotally supported in the housing and comprising an articulated, quadrilateral structure, one of whose elements constitutes a locking member for the sear hook adapted to engage and lock the latter in breech block arresting position, a second element of said quadrilateral structure being arranged to be engaged and driven by the breech block during its passage through its rear portion of travel to carry the locking member back into the locking position after a period of release of said member, a third element of said quadrilateral structure acting as a release lever for th locking member, the fourth element of said structure operating as a connecting link, a trigger member operable to cause tripping of the release lever with resulting disengagement of the said second element from the breech block, whereupon the locking member becomes movable to non-locking position, and means for urging said locking member towards unlocking position.

2. The combination according to claim 1, including a buffer casing disposed within the housing, the sear hook and quadrilateral structure being mounted in such casing, the trigger mem ber being carrie by the housing, and connecting means includ g a force-transmitting sliding coupling between the trigger member and the release lever.

3. The combination according to claim 1, including a buffer casing surrounding the breech block and a plurality of springs arranged within 0 the wall of the casing parallel to the axis of the breech block and acting against the housing.

4. The combination according to claim 1. including a driver arranged to actuate the release lever, means for transmitting movement from catches the breech closing body 6 by means of the trigger member to the driver, said third eleinon with the driver on a pivot pin coaxial with ment surrounding the locking member in strap fashion, the second element or the quadrilateral structure being connected with the locking member and being connected to the release lever by the fourth element, said second element having a stop thereon, and two control pawls on the breech block body, one of said pawls being engageable with the said stop to bring the locking member into sear hook locking position, and the in series at the rear of the quadrilateral struc-. ture, the center pin lying in the central longi-' tudinal plane of the firearm and acting on the locking member to urge the same into sear hook the axis of rotation of the release lever in the position of rest, a pawl on the carrier biasedto the coupling position and adapted to be coupled with the driver, and a release rod adapted to be controlled by the magazine charger and movable into the housing, said release rod being operable to cause uncoupling of said pawl.

7. The combination according to claim 1, including a driver arranged to operate the release lever, the release lever being pivoted intermediate its ends, a pawl carrier coupled with the trigger member and rotatably carried in common with the driver on a pivot pin coaxial with the axis of rotation of the release lever in the position of rest, a pawl on the carrier biased to the coureleasing position upon tripping of the release pling position and adapted to be coupled with the driver, a release rod adapted to be controlledby the magazine charger and movable into the housing, said release rod being axially movable in the tion.

HANNS LIPPERT. 

